My son has a 2002 HO dodge cummins, with 6-speed. He says that you can
pull horses, whatever, up hills or whatever. He has seen no advise not to in his manual.
I thought that you should treat that 6th gear much like you do in 47RE auto.
Any body got any light to shed?

HJH

 

i would pull it 5th in a 5 speed, 4th in a auto and 6th in a 6 speed, it won't hurt anything. the 5 speed is a bit dangerous to pull below 1500 rpm, because the 5th gear nut could spin off.

 

Definitely use 6th. The NV5600 is a heavy duty trans designed to pull. There are many trucks on here that have over 300k on them and have pulled huge loads in 6th the entire time... This isn't a light truck that needs to be babied, besides top speed in 5th will DRINK fuel and your limited to max 55-60mph... Don't worry about the tranny, it'll pull anything you want.

 

echo syndrome... this 6-speed is as stout as they come. 5th gear @ sustained highway speeds(65-70) is going to drink fuel by the gallon/mile...

 

The torque curve on this engine reveals that it's better off a bit lower on RPM's as well. Sort of the opposite idea of a gas engine. The 5.9 is best off being left lower in the revs as much as possible.